Wireless receiving static eliminator



y A. G. ANDERSON 1,803,419

WIRELESS RECEIVING STATIC ELIIINATOR Filed June 26. 1930 v INVEN TO RPatented May 5, 1931 I ALEXANDER GRAHAM ANDERSON, F WHITELAND, INDIANAWIRELESS RECEIVING STATIC ELIMINATOR Application filed June 26,

My invention relates to the elimination or reduction of static, stationinterference, and any other electrical interference due to alternatingor varying electric current or voltage,

and employs the following means.

0 rial-frequency; and the other of said balancing circuits being tunedto receive fre-' quencies slightly higher than the desiredsignail-frequency.

2. A four-circuit inductor for separating static from the desiredsignal. This tourcircuit inductor, to be known as the'first inductor,consists of a primary, twov -closely coupled secondaries, and aloosely-coupled secondary. The primary performs the usual primaryfunction of receiving the varying electric energy and converting it intoan electromagnetic field, in which magnetic field the damped staticenergy remains relatively close to the primary, and the undamped sigcalenergy reaches out beyond the static enorgy. The two closely-coupledsecondaries occupy the portion of the magnetic field where the staticis, and the loosely-coupled secondary occupies the portion of themagnetic field where the signal energy reaches.

3. A four-circuit inductor for neutralizing the static component ofelectric energy associated with the signal. This four-circuit inductor,to be known as the second induct-or, consists of three primaries and asecondary. Two of these primaries are connected thru the two tunedbalancing circuits to the two clo ely-coupled secondaries of the firstinductor and receive the separated static component. The third primaryof this second inductor is in opposite phase to its other two primariesand connects thru the tuned signal-circuit to the loosely-coupledsecondary of the first inductor and receivesthe signal 5 energy. Thesecondary of this second inductor connects Withthe receiver. All theprimaries of the two inductors are preferably grounded.

The electric process which takes place is as follows. Due to the tuningof the three 1930. Serial No. 463,950.

circuits the greater part of the signal energy goes thru the signalcircuit, because the slgnal-circuit'is tuned for the signal-frequency,and the two balancing circuits are tuned, one above and the other below,the signal-frequency. All three circuits receive a part of the staticenergy, but because the secondaries of the two balancing circuits occupythe portion ofithe magnetic field where the static prevails, the staticenergy is partial to-the two balancing circuits, while the signal energyis partial to the signal-circuit. By tuning the two balancing circuitscorrectly the two together will receive the same amount of static energyas goes thru the signal-circuit, while the greater part of the signalenergy Iwillgo thru the signal-circuit. The static component that goesthru the two balancing circuits and the static component that goes thruthe signal-circuit are received by the three primaries of the secondinductor and neutralize each other. The signal energy also sulfers tosome. extent from this: neutralizing process, of the signal energygoesthru the balancing but since only asmall part circuits, the signalenergy is only slightly neutralized. The secondarv of the secondinductor picksup the static-free component of signal energy that remainsafter the neutralizing process, and carries it to the receiver. For bestresults these two four-circuit inductors should be shielded withgrounded shields. as this prevents picking up fresh static from theatmosphere.

The accompanying drawing illustrates the use ofmy invention between theantenna and the input circuit of a receiver, but the invention may beused between, the adjacent parts of any signal-bearing circuit.

The inductors shown in the accompanying drawing are of the coil type,but any type of suitable inductors may be used.

In the accompanying drawing, A, represents the antenna, R the receiver,P the pri-' maryof the first inductor, S the looselycoupledsignal-receiving secondary of the first inductor, S the closely-coupledsecondary of the first inductor for receiving lowfrequency static,'S theclosely-coupled secondary of the first inductor for receiving iii)high-frequency static, P the primary of the second inductor forreceiving signal energy, P the primary of the second inductor forreceiving low-frequency static, 2 the primary of the second inductor forreceiving hi gh-frequency static, S the signal-receiving secondary ofthe second inductor, K the tuning condenser for the signal-circuit, Kthe tuning condenser for the low-frequency balancing circuit, K thetuning condenser for the high-frequency balancing circuit, G the groundfor primary P, G the ground for primary P, G the ground for primary P Gthe ground for primary P I claim:

1. A static and interference eliminator, adapted for connection betweenthe antenna and input circuit of a receiver, which consists of twofour-circuit inductors coupled by two balancing circuits and asingle-circuit; the first four-circuit inductor consisting of a primary,two closely-coupled secondaries and a loosely-coupled secondary, and thesec ond four-circuit inductor consisting of three primaries and asecondary; the two closelycoupled secondaries of the first four-circuitinductor being parts of balancing circuits, one tuned slightly above andthe other slightly below the receiver tuning, and the looselycoupledsecondary of the first four-circuit 1nductor being a part of the signalcircuit tuned with the receiver; the two closelycoupled balancingsecondaries of the first four-circuit inductor being connected thrutuning condensers to two of the primaries of the second four-circuitinductor which two pri maries are in opposite phase to the third primaryof the second four-circuit inductor; the loosely-coupled signalreceiving secondary of the first four-circuit inductor being connectedthru a tuning condenser to the 'iird primary of the second four-circuitinductor; the primary'of the first four-circuit inductor being connectedwith the antenna, and the secondary of the second four-circuit inductorbeing connected with the receiver; all of the primaries being grounded.

2. A static and interference eliminator, adapted for connection betweenadjacent parts of a signal-bearing circuit, which consists of twotour-circuit inductors coupled by two balancing circuits and asignal-circuit; the first four-circuit inductor consisting of a primary,two closely-coupled secondaries and a loosely-coupled secondary, and thesecond four-circuit inductor consisting of three primaries and asecondary; the two closely-coupled secondaries of the first four-circuitinductor being parts of the balancing circuits, one tuned slightly aboveand the other slightly below the receiver tuning, and the looselycoupledsecondary of the first four-circuit inductor being a part of the signalcircuit tuned with the receiver; the two ClOSGlY-COH- pled balancingsecondaries of the first tourcircuit inductor being connected thrutuning condensers to two of the primaries of the second four-circuitinductor which two primaries are in opposite phase to the third primaryoi the secondary tour-circuit inductor; the loosely-couplcdsignal1'eceiving secondary of the first four-circuit inductor beingconnected thru a tuning condenser to the third primary of the secondfour-circuit inductor; the primary of the first four-circuit inductorbeing connected electrically with the preceding part of the adjacentsignal-bearing circuit, and the secondary of the second fourcircuitinductor being connected electrically with the succeeding, part of theadjacent signal-bearing circuit.

3. A static and interference eliminator, adapted for connection betweenadjacent parts of a signal-bearii'ig circuit; which consists of twomulti-circuit inductors coupled by a signal circuit and one or morebalancing circuits; the first multi-circuit in ductor consisting of aprimary a signal-1e ceiving secondary and one or more static-receivingsecondaries coupled in the prevailing static-portion of the primarysfield; the second multi-circnit inductor consisting of a normal-phaseprimary and one or more opposite-phase primaries and a secondary; the sinal-receiving secondary of the first multicircuit inductor and thenormal-phase primary of the second multi-circuit inductor being parts ofthe signal circuit tuned with the receiver; the static-receivingsecondary or secondaries of the first multi-circuit inductor and theopposite-phase primary or primaries of the second multi-circuit inductorbeing parts of the balancing circuit or circuits tuned either slightlyabove or below the receiver tuning; the primary of the firstmulticircuit inductor being connected electrically with the precedingpart of the adjacent signal-bearing circuit; and the secondary of thesecond multi-circuit inductor being connected electrically with thesucceeding part of the adjacent signal-bearin circuit.

ALEXANDER GRAl IAM ANDERSON.

